The invention relates generally to fluid pumping and collection apparatuses. More particularly, the present invention relates primarily to such apparatus for pumping, recovering, collecting, or controlling fluids such as groundwater samples, condensate, hazardous leachate materials, or contaminated fluids from sources such as contaminated landsites having one or more in-ground wells, for example, or to or from tanks or other vessels. It should be noted, however, that the invention is also applicable and adaptable in various other applications that will occur to one skilled in the art from the disclosure herein, and that the invention allows for pumping in substantially any pump orientation.
Recent increases in public concern for the environment have resulted in various government-imposed environmental regulations with regard to groundwater quality and landsite cleanup projects. Among such regulations are requirements relating to the monitoring and sampling of groundwater quality. In response to these requirements, water quality analytic capabilities have ben improved and water sampling equipment has been developed. Much of the previously-developed sampling equipment has not been effective, however, in obtaining consistent, non-contaminated water samples that are accurately representative of the water system from which the sample is taken. Such ineffectiveness is especially acute in situations where vertical pump orientations are impossible or impractical.
The inadequacies of previous sampling equipment stem largely from causes such as cross-contamination between sampling sites, ineffective and inconsistent field cleaning methods, contamination due to equipment handling, and inconsistent well depth sampling. In addition to present sample quality problems, much of the previous equipment has been heavy and bulky and thus difficult to transport from one monitoring site to another. Finally, much of such previous equipment has proved to be complicated to operate, inordinately expensive, impractical for sampling at remote locations where site access is severely limited, and/or unusable in applications that require pump orientations other than substantially vertical.
The cleanup of toxic or otherwise hazardous materials from contaminated dump sites has also presented monumental environmental problems, especially in terms of safety, effectiveness, and economics. Many of the hazardous materials present in such contaminated landsites, or other fluid materials in other applications, are difficult and dangerous to handle, convey, and collect, especially in situations where the fluid is practically inaccessible to pumping equipment that requires a vertical orientation, as well as often being highly aggressive and corrosive to many materials commonly used for removal and collections equipment construction. In addition, many hazardous materials give off, or are accompanied by, explosive gases, making the use of conventional electrically-operated equipment at contaminated landsites dangerous and undesirable. Finally, because of the potentially dangerous nature of many of the hazardous materials at such landsites, human intervention in the operation and maintenance of cleanup systems and equipment must be minimized.
In response to the groundwater monitoring and hazardous waste cleanup problems discussed above, the above-mentioned issued patents and co-pending applications relate to fluid sampling apparatuses provided for use in obtaining accurate samples of groundwater or other fluids. In one preferred embodiment of the disclosed groundwater sampling equipment, for example, a groundwater sampling pump is dedicated to a particular monitoring well or other sampling site in order to substantially avoid cross-contamination of samples for site-to-site and is constructed from lightweight, non-contaminating materials.
One of the preferred pumps for sampling or other pumping applications is a submersible, fluid-actuated pump wherein the actuating fluid is preferably a gas such as air. A flexible bladder member in this type of pump separates and isolates the interior of the pump into two chambers; a first chamber that contains the sample fluid and is in communication with both the pump inlet and outlet, and a second chamber surrounding the first chamber, and connected to a source of the actuating gas, with the bladder disposed therebetween. The pumped fluid is conveyed through the pump by alternately pressurizing and venting or relieving the pressure in the second chamber to contract and relax the bladder member, thus alternately decreasing and increasing the volume of the first chamber. The pumped fluid is drawn into the first chamber during such increases in volume under the influence of the natural hydrostatic head of the groundwater or other pumped fluid and is discharged through the pump outlet during such decreases in volume, thereby conveying the pumped fluid through the pump. The components of this pump are preferably composed of low-cost, lightweight synthetic materials that are non-corrosive and do not otherwise affect the chemical composition of the sampled fluid, but other materials, such as stainless still can alternately be used in appropriate liquid pumping applications. In this regard, it should be stressed that the present invention is not limited to such bladder-type pumps and is equally applicable to other types of pumps.
In order to allow the pump to be used in non-vertical orientations, that is in orientations greater than approximately 30 degrees from vertical, the preferred pump (whether a bladder-type or a non-bladder pump) includes rather unique reed-type check valves that render the pump functional in such non-vertical orientations, in substantially horizontal orientations, or even in inverted orientations. Such reed check valves are primarily used in gas conveying applications, but have been found to be highly advantageous in liquid pumping applications, according to the present invention, due to the fact that such reed check valves require only very low pressure levels to operate. In contrast, conventional check valves capable of functioning in non-vertical orientations, such as those employing a ball-and-seat arrangement with a spring return, require much higher pressures in order to function.
Also, in applications requiring substantially horizontal pump applications, the pump can include a flexible hose-like fluid conduit attached at one end in fluid communication with the pump inlet, with the other, open hose inlet end being submerged in the liquid to be pumped. In this embodiment, the open hose inlet end can be weighted in order to deflect the flexible hose downwardly, thus facilitating pumping down to minimum liquid levels in such horizontal, or near-horizontal, orientations.
When used for sampling, for example, the pump can be preferably dedicated to, and thus remains in, a particular sampling site or well, which is substantially isolated from the above-ground surroundings by a wellhead assembly in order to reduce potential contamination during sampling. A portable controller apparatus can be provided with quick connect-disconnect means and means for alternately pressurizing and de-pressurizing the actuating fluid. The fluid sampling apparatus, or other such apparatus, may also optionally include means for measuring the standing level, and thus the hydrostatic had, of the fluid in the well, tank, vessel, or other liquid source.
Besides relating generally to the above-described groundwater quality applications, another of the primary objects of the present invention is to provide a pump usable in the recovery, collection, and control system for the removal of hazardous leachate or other liquid materials, wherein the system and equipment are relatively simple and economical to install, operate, and maintain, and require a minimum of human intervention. The present invention also seeks to provide such a pump applicable to systems wherein the recovery, collection, and control system and equipment do not require the presence of electricity and are composed of materials that are resistant to, and substantially unaffected by, the corrosive and destructive nature of many hazardous materials. In addition, the present invention is, of course, directed to improving the safety, effectiveness, and wide applicability of such equipment.
According to the present invention, a pump is provided for a wide variety of applications, including but not limited to withdrawing and collecting a flowable hazardous leachate material, a contaminated groundwater, or other subterranean liquids from a landsite having a plurality of in-ground wells, and especially in systems where in accessibility or other factors substantially preventing a vertical, upright pump orientation, thus requiring a horizontal, non-vertical, or even inverted orientations. The system can include a plurality of pumps, each of which is adapted for installation in one of the in-ground wells at the landsite, can have an associated fluid control apparatus for supplying and controlling an operating fluid to the pump, and can be installed in small-diameter wells, generally in the range of approximately two inches to approximately ten inches in diameter, for example. As mentioned above, the present invention renders a pump especially advantageous for pumping from horizontally, or near-horizontally, drilled wells below waste sites for sampling or cleanup.
The system can also involve collection equipment for receiving and collecting the leachate or other liquid material withdrawn by the fluid-operated pumps. Such collecting equipment can also include one or more flow totalization devices for receiving and collecting the leachate material from the pumps, with piping or other conveying apparatus being provided for conveying the leachate or other liquid material from the pumps to the totalization device and for conveying the collected leachate or other material from the flow totalization device to holding or disposal equipment.
Such a flow totalization device according to one exemplary application of the present invention includes a cyclable discharge device that is self-actuable and self-deactuable for discharging the collected leachate or other material to the holding or disposal equipment during each actuation/deactuation cycle of operation. In such an arrangement, a counter device is preferably providing for counting the number of actuation/deactuation cycles, in which a predetermined volume of liquid material is charged during each cycle. The counter device thus allows the total volume of collected liquid material discharged from the flow totalization device to be measured and accounted for over a preselected time period. In systems employing a number of such flow totalization devices, each receiving liquid material from a number of the plurality of pumps, the invention preferably includes a common disposal or holding tank into which the flow totalization devices are discharged. Alternately, the flow totalization devices may be discharged directly into a railway tank car, a tank truck, or other portable collection receptable, which when full can be replaced and transported away for appropriate disposal or treatment of the hazardous material.
The preferred leachate recovery pumps for withdrawing the leachate material from the in-ground wells are air-operated, gas-displacement pumps, each having a generally hollow cylindrical body submersible in the in-ground well. The pump body includes a water, leachate, or other liquid inlet with an inlet reed check valve such as that described above for allowing substantially one-way fluid flow from the in-ground well into the housing interior, and a water, leachate, or other liquid outlet with a similar outlet reed check valve allowing substantially one-way fluid flow from the pump body interior to the discharge conveying and collection equipment. A discharge tube is disposed within the pump body and has an inlet end that is open to the pump body interior. It should again be noted that in this preferred form of pump according to the present invention, the inlet and outlet check valves are capable of allowing the pump to function in any orientation, including vertical and upright, generally horizontal, non-vertical, or even inverted orientations, whether or not a bladder-type pump or other type of pump is used.
An exemplary control apparatus in some applications for supplying and controlling an operating fluid for a gas-displacement pump pulsatingly supplies a pressurized operating fluid, such as air, into the pump body interior in order to forcibly displace and discharge leachate or other liquid material through the discharge tube and the outlet. Between pressurized pulses of the operating fluid, the control apparatus relieves the pressure of the other operating fluid in the pump body interior in order to permit liquid material to flow, under the influence of its own hydrostatic head, into the pump housing through The inlet. The preferred control apparatus in such exemplary applications is all pneumatic and also includes conveniently-adjustable level sensing device for sensing the level of the leachate or other liquid material in the in-ground well in order to selectively actuate and deactuate the pump in response to respective high and low liquid levels in the in-ground well. In addition, a second level sensing system can also be provided for sensing the level of collected material in a central holding or collection apparatus and is interconnected with the control apparatus to deactuate the recovery pump (or pumps) when the collection or holding apparatus is too full to accept more liquid material. The control apparatus then prevents further actuation of the pumps until the central collection apparatus is emptied, replaced, or otherwise rendered capable of receiving additional collected liquid material.
Additional objects, advantages and features of the present invention will become apparent from the following description and appended claims taken in conjunction with the accompanying drawings.